The Valve,safety Relief, cataloged under National Stock Number 4820-01-340-0643, is classified within Federal Supply Class 4820 (Valves, Nonpowered) of the Valves group. Government technical data includes 20 specifications, cited from the U.S. Government catalog. 3 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 4820-01-340-0643 |
| Item Name | Valve,safety Relief |
| FSC / FSG | 4820 / 48 — Valves, Nonpowered |
| Status | ACTIVE |
| Flow Control Device | DISK |
| Connection Style | PLAIN,OPTIONAL END(PIPE) SECOND END |
| Connection Style | PLAIN (PIPE) FIRST END |
| Connection Type | THREADED INTERNAL PIPE SECOND END |
| Connection Type | THREADED EXTERNAL PIPE FIRST END |
| Style Designator | ANGLE |
| Operating Pressure | 500.0 POUNDS PER SQUARE INCH (PSI) MAXIMUM SINGLE RESPONSE LBS |
| Adjustable Pressure Range | +185.0 TO 206.0 POUNDS PER SQUARE INCH LBS |
| Bonnet Type | INSIDE SPRING |
| Thread Direction | RIGHT-HAND ALL ENDS |
| Nominal Thread Size | 2.000 INCHES FIRST END IN |
| Nominal Thread Size | 2.500 INCHES SECOND END IN |
| Maximum Operating Temp | 400.0 FAHRENHEIT SINGLE RESPONSE DEGF |
| Disk Loading Method | SPRING |
| Bonnet Attachment Method | INTEGRAL |
| Material | STEEL CORROSION RESISTING FLOW CONTROL DEVICE |
| Material | STEEL CORROSION RESISTING BODY |
| Material | STEEL STEM |
| Thread Series Designator | NPT ALL ENDS |
| Valve Operation Method | AUTOMATIC |
| Acquisition Status | ACTIVE |
| DEMIL Code | DEMIL A — No Demilitarization Required |
| Hazard | No hazard code in the DLA record (HMIC N) |
| Criticality Code | X |
| Reference | Meaning |
|---|---|
| 1982C 2X2 5IN 185T 206PSI | 5/9 Secondary reference Dresser, Inc. Dba Dresser Equipment Group Div Industrial Valve Operations, Dresse |
| 315086 | D/9 Drawing number reference only Dresser, Inc. Dba Dresser Equipment Group Div Industrial Valve Operations, Dresse |
| 1982C 2X2.5IN.185T206PSI | 3/9 Design control — primary reference Dresser, Inc. Dba Dresser Equipment Group Div Industrial Valve Operations, Dresse |
NSN 4820-01-340-0643 is a Valve,safety Relief, classified under FSC 4820, Valves, Nonpowered. Status: active.
Key specifications for 4820-01-340-0643: Flow Control Device: DISK; Connection Style: PLAIN,OPTIONAL END(PIPE) SECOND END; Connection Style: PLAIN (PIPE) FIRST END; Connection Type: THREADED INTERNAL PIPE SECOND END. 20 specifications are documented in the U.S. Government catalog.
No hazard code in the DLA record (HMIC N). Hazard information on this page is shown exactly as it appears in the DLA record.
U.S. Government catalog: edition PUBLOGDVD v12.0.0 (OCT 2026), edition date 2026-10-01, retrieved 2026-10-16.
U.S. Government catalog: edition PUBLOGDVD v12.0.0 (OCT 2026), edition date 2026-10-01, retrieved 2026-10-18.